Poisonous plants are one of the most important causes of poisonings in human. Although most of plant-induced poisonings are mild in terms of severity but they may be life-threatening. Regarding compositions of toxic plants, most of them can induce toxicity on many biological systems including central nervous system, cardiovascular, hematopoietic sytem and etc. In this brief review, we tried to summarize demonstrations of toxicity and adverse effects of poisonous plants and their active substances on biological systems, and thir clinical management.

Background: Because in today's societies, not only the nutritional role of plants and fungi is very high, but also the main basis of many drugs are plants and plant products, therefore one of the problems of clinical toxicologists is the toxicity of these products.
Objective: This study aimed to define the prevalence, symptoms, complications, effective treatments, type of substance use, the cause of intake, location, gender distribution and age of poisoning with herbs and mushrooms in hospitalized patients of Loghman Hakim Hospital in Tehran.
Methods: This is a retrospective study with questionnaire formulation. Patients reviewed from the beginning of 2007 to the end of 2013.
Results: of 103 cases of poisoning with plants and mushrooms 64.1% were male, and 35.9% were female. The mean age of patients was 21.59 ± 30.51 years. The most commonly used substance is Datura (34%). On the other hand, sole mushroom ingestion was found in 5.8% of cases. The most significant source of plants and mushrooms was reported from herbal-shops (27.18%). The reason behind intake was either random or euphoria. Four patients were admitted to the intensive care unit, and three patients needed intubation. The mean hospital stay was 1.64 ± 1.28 days. Ninety percent of the treatments were supportive, and 75.7% of the patients recovered without any clinical complications.
Conclusion: Poisoning with toxic plants and mushrooms is one of the frequent causes of intoxication that is often accidental. In children poisoning is inadvertent, but youth are more likely wanted to have euphoria. Treatment strategies are supportive and symptomatic.